This invention is directed to the problem of mounting the lower stamping of the diaphragm head assembly to a thermostatic valve body. Most commonly this has been done by silver soldering the head to the body. This procedure involves a considerable amount of labor and requires the use of torches and acid baths in the production area, none of which is desirable. Furthermore, allowance must be made for subsequent finish machine work directly related to the processing involved in the soldering operation and otherwise unnecessary. Thus the method is not very desirable, either from a production, health, or cost standpoint.
Some designs have screwed the head stamping onto the body and sealed the stamping to the body with epoxy or an O-ring. To provide the screw threads on the stamping requires that the stamping have a drawn neck which is difficult to produce and also requires threading the neck which is an added production cost. The net result was a substantially higher cost.
There have been attempts to crimp the head to the body but prior efforts did not get high enough unit pressure to cause an effective seal to be made.